Organ transplantation is currently performed as the main therapy for irreversible dysfunction of organs due to illness or accidents. Although the number of transplantation cases has increased and their success rates have dramatically risen due to advance in immunosuppressive drug and transplantation technology, chronic shortage of organs has come to be a serious problem in transplantation medicine (Non-Patent Document 1). Although a method of transplanting organs from transplantation animals or development of genetically modified animals which are less likely to produce immunological rejection (Non-Patent Documents 2 and 3), as well as development of artificial organs which aims to replace an organ function with an artificial material (Non-Patent Document 4) are being carried out in order to overcome this organ shortage, none of the technological developments have yet to replace the functions of adult organs.
Major reasons for shortage of donor organs supplied for transplantation are not only the number of organs provided, but also the short period of time that the removed organ can be preserved in a transplantable state. For this reason, development of technology to preserve the removed organ ex vivo in a transplantable state for a long time is being promoted. The most widely employed method today is cold storage of replacing blood within the organ with a low-temperature organ preservation solution to suppress cell metabolism, and then immersing it in a low-temperature preservation solution. There is also a cold perfusion method of immersion preservation at a low temperature while perfusing the vascular network within the organ with a low-temperature organ preservation solution, the purpose of which is removing the waste product within the preserved organ. Trials for this are recently being carried out in Europe and the United States (Non-Patent Document 5). However, there is a limit to the period of time which organs preserved with these methods can be safely used (for example, the limit of use for liver by cold storage is thought to be 20 hours), and a technology for further extending the preservation period is in need.
As a device for long-term preservation of liver, an artificial organ system is proposed, wherein an organ hanging tube is inserted into the inferior vena cava stump of the liver, the entire liver is hanged, and the liver is supported by said hanger tube and the surface of a container part the liver is placed upon, which may allow it to be kept in a dilated state (See, e.g., paragraph [0024] of Patent Document 1, FIG. 2, and FIG. 4).